Combined telephone and automatic fire-alarm system



(No Model.)

2 Sheets-Shee'c- 1; T. D. LOUKWOOD.

COMBINED TELEPHONE AND AUTOMATIG FIRE ALARMSYSTEM.

No. 308,566. v

Patented Nov. 25, 1884.

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(No Model.) 2 SheetsSheet- 2.

I T. D. LOGKWO-OD. I G'OMBINED TELEPHONE AND AUTOMATIC FIRE ALARM SYSTEM. No. 308,566. Patented NW. 25, 18 84.

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r a so "Unrrn STATES PATENT OFFICE.

THOMAS D. LOOKlVOOD, OF MALDEN, MASSACHUSETTS.

COMBINED TELEPHONE ANaD AUTOMATIC FIRE-ALARM SYSTEM.

SPECIFICATION forming part of Letters Patent No. 308,566, dated November 25, 1884-.

Application filed June 26, 1884.

To all whom it may concern:

Be it known that I, THOMAS D. Loonwoon, of Malden, in the county of Middlesex and State of Massachusetts, have invented certain Improvements in Combined Telephone and Automatic Fire-Alarm Systems, of which the following is a specification.

My invention relates to the utilization o telephonic circuits, connecting a series of substations with a central station for the purpose of automatic fire-alarm telegraphs, in addition to their ordinary use of telephonic communi cation.

Telephonic exchange circuits, especially those connecting with the offices of business men, are, as at present arranged, idle and useless during a great part of the day and during the entire night, and to provide facilities enabling them to be used for fire-alarm purposes, whereby great economy in construc tion and maintenance may be effected, is the object of my invention.

To this end it consists in providing a subscribers main line with switching or circuitchanging devices at both central and sub-stations, those at the sub-stations being capable of either manual or automatic operation; and in combining the said main line and circuitchangers at the several sub-stations with a suitable telephonic outfit, and also with alarmtransmitting devices, and at the central station with telephones, telephone call signals, and with co-operative fire-alarm-receiving apparatus.

It further consists in certain circuit arrangements whereby telephonic communication may be maintained with the sub-station, even when the fire-alarm is connected with the main line, so that if the subscriber should omit to disconnect the alarm in the day-time the telephonic service will be in no wise impaired.

In the accompanying drawings, Figure 1 is a diagram showing the electrical connections, and of the several devices of my combined system. Fig. 2 is a diagram of the centraloffice terminals of a series of telephone and alarm wires, and their connection by means of a switch-board with telephone and alarm sig nal receiving instruments. Fig. 3 is a skeleton representation of the designating signalboX connected with the fire-alarm circuits.

(No model.)

Fig. 4 is a diagram representing the alarmstation of the system connected to a way-station. Fig. 5 is a modification of the setting device, and Fig. 6 is a perspective View of the thermostat I prefer to use.

Referring to the drawings, 0 0 represent the central office of a telephoneexchange system, at which, in a manner well understood, telephone main lines L L, connecting with a series of sub-stations, are centered for the purpose of affording, by means of a switch-board and suitable signaling and telephonic apparatus, oral communication between the sev- 6 5 eral sub-stations.

In Fig. l the several lines are shown as each passing through an electromagnetic annunciator, 13, and by means of a switch, 8, to a common ground-wire, 5, which represents the normal condition of the circuits at the central station. The switch S may, when the alarms are set at the sub-stations, be turned onto the stud J, thus disconnecting the main lines from the ground-wire 5, and connecting them with the ground through the relay P and the battery M B by means of the wires 1 and 2. The said relay controls the circuit of the local battery L B, which circuit includes a signalbell, E, and a register, A, and is normally open at the relay-points 0'. When the relay is energized by the closing of the main circuit, and the consequent activity of the battery M B, the local circuit is closed, and the alarm-signal is struck upon the bell E and re- 8 5 corded on the register A.

In Fig. 2 a modified arrangement of the central-office circuits is shown, which is in some respects preferable, as indicating the use of the ordinary telephone switch-board,whereby the several circuits may be connected together. When this plan is adopted it is obvious that only such circuits as are provided with firealarms need be disconnected from the normal ground-connection and connected with the relay and battery branch.

In the drawings, a switch-board, S B, of any desired character, is provided, to which the line-wires L, after passing the annunciators i, are connected. The several vertical conducting-bars y are normally united by plug-counectors p at the intersecting points to the transverse conducting-bar z, and the line-circuits are thus connected directly to earth.

\Vhen it is desired to communicate telealarmaeceiving instruments, as hereinbcl'ore described.

I will now describe the connections and apparatus at the sub-station or at the premises to be protected. The incoming line L from the central station, 0 O, on entering the substation S passes by wire 9 to magneto bell-box M, to which the receiving and transmitting telephones are attached in the usual manner. The course of the line after passing the said bell-boX is by wire 4 to switch s,which,during the day, or when the firealarm system is not in an operative condition, is set 011 the button 9, connecting thereby with wire 8, leading to the spring-bar c. This baris provided with a back contact or bridge, a, which, by means of the wire 11, is united with the ground at G; and when the door D is open the spring-bar, by its own resiliency, presses against the back contact, thus putting the line through the tele iihone-instruments direct to ground. This will be the condition of the line during business hours, and so far it differs in no way from that of the ordinary telephone-line. I affix the spring-bar 0 preferably to a door,which is generally retained open during business hours, but which is uniformly closed when business is over or during the nightsuch, for exam ple, as the door of an inner or private oliice and by this arrangement I accomplish the automatic setting of the alarm, as the closing of the door is adapted to force away the springbar a from the normal ground-contact n and against the front contact, a, with which the spring-bar c is also provided.

To enable the door to engage properly with the bar 0, the said bar must be bent first in wardly at right angles for a distance equal to the thickness of the door to correspond with the corner of the door-post, and again at right angles to the first bend, so that the end projects outwardly and in the path of the edge of the closing door; or, if preferred, the springbar may be left straight, and a projecting piece or plate of metal screwed or otherwise affixed to the door to engage therewith. The front contact, a, leads by wire 10 and wire 18 to the alarm-circuits 7 7 7. These may be constructed in the following manner: Thermostats of any desired character are attached to as many suitable points upon the walls and ceiling as may be considered necessary. I prefer the form of thermostat shown in Fig. (3.v In this form a plate or frame, q, of brass or any similar material, supports a glass tube, K, which contains a certain amount of mercury. The mercury normally remains at one end of the tube, and wires 7 and 8 are introduced into the ends of the tube, which is then hermetically sealed. One of the wires is also at all times in contact with the mercury, while the end of the other wire is normally at a suitable distance therefrom. Vhen the temperature of the surrounding atmosphere rises, the mercury expands in the tube and at any designated degree previously determined makes contact with the second wire, and thus closes the circuit. The several wires 7 are each united to the wire 7 of the then mostats, and a signal-box, c, which I show in diagram by Fig. 3, is introduced into the circuit. An alarm-bell of any preferred construction may also be introduced into the circuit, so as to give a local alarm to any person who may be in the building. A ground-wire, 6', is branched by wires 8 to each of thermostats, as shown, and connected to the short wires j of the said thermostats, but inasmuch as the wires 7 and have no normal electrical contact within the thermostat, the groundwires do not at any ordinarytemperature complete the circuit, and the alarm, though ready for action, is not given.

As shown in Fig. 3, the signal-box I comprises a signal-wheel, 10, adapted to transmit any designated signal by means of the spaces a cut in or non-conducting pieces let in its periphery, and driven by a train of clockwork. (Not shown.) The wheel and clockwork is maintained normally at rest by-the engagement of the armature-lever s with the stops it 1 The armature s, carrying this lever, is controlled by the electro-magnet a, and the branch circuit 7 is led through the said electro-magnet and circuit-whecl by means of the screw-posts p, the wires 13, 14, and 15, the substance and axis of the wheel, and the contact-springs s and 8*. XVhen the circuit through the electro-magnet x is closed, the armatureis attracted, the clock-train released, and the signal given. One of these signalboxes is placed at every floor, if desired, and may be constructed to give a floor as well as a house signal. The small buttonswitch s is not an absolute necessity, but is introduced to indicate that the alarm, if desired, maybe manually set. It may also be adopted as an ad ditional precaution in case the spring-bar 0 should ever fail to work properly.

Should it become necessary to use the telephone while the alarm is set or before opening the door D in the morning, this can readily be accomplished by the means which I am now about to describe, so that the telephone is always adapted for operation independent of the condition of the firealarm circuit. An additional ground-wire, 5, is led from the junction of the wires 10 and 18, and passes to a high but adjustable resistance, It, and thence to the ground; and as rhythmical electrical vibrationssuch as those used in telephonypass readily through condensers, I bridge the IIO resistance or rheostat It with the condenser C. An earth circuit perfectly adapted for the transmission of articulate speech is thus provided. In the operation of this system, should the temperature of any part of the protected building rise to an abnormal height, the mercury in the thermostat h at that point expands and connects the short branch groundwire j with the branch circuit-wire 7, closing the circuit of the central-office battery M B through the transmitting-signal box 0 and alarm-bell B at the sub-station and through the relay P at the central station. The signal-wheel in the boX being released rotates, giving the signal, which is repeated by the relay at the central station on the register and bell in the local circuit, and is simultaneously struck on the substation bell B. The central-office operator, after receiving the alarm, may telephone it to the fire department or otherwise dispose of it, as his duty may require.

In case where there is no door which is uniformly kept open during the day and closed at night, the setting device shown in Fig. 5 may be substituted. In this modification the alarm-circuit spring d, connecting by wire to with the main line, is adapted to be acted upon by the bolt B of the door-lock IV, and when the door is locked for the night is pressed by the said bolt against the front contact, 20, which leads to the alarm-circuit.

In Fig. 4 I show a plan for combining the fire-alarm with a way telephone-station in contradistinction to a terminal station. In this case the main line L, after passing through the telephone-instruments, is continued, as usual, outward to the next station. A branch wire, 20, is united to the main wire and leads to the spring-bar c,which,when the door Dis closed, is pressed upon the plate a, connecting with the alarnrcircuits 2, 3, 4:, 5, and 6, as hereinbefore described. It is of course not necessary that the alarm announcing and recording instruments should be located at thetelephon'e central station, although I prefer such an arrangement. They may be placed at the firetelegraph headquarters, and the wire 1 in Figs. 1 and 2 will in that event be of course extended from the switch S or the switch board cross-bar z to such location. Furthermorc,in lieu of placing asignal-box with house and floor signals on each floor of the building to be protected, I may, if I so elect, provide but one signal-box for each building, and designate the precise location of the undue heat by suitable annunciatorsv I make no claim herein to the special form of thermostat or signal-box used, or to the special arrangement of the fire-alarm circuits with relation to said thermostats and signalboxes, as such instrumentalities and arrangements are, per se, old; but

That I do claim, and desire to protect by Letters Patent, is

1. An electrical system designed both for oral communication and for automatically giving an alarm of fire, said system comprising a central station at which are placed signalin g and telephonic instruments, fire-signalreceiving devices, and switches or circuit-' changers for connecting any two lines for telephonic communication, or for connecting any line with said firesignaling instruments, a main line or lines extending from said central office to a sub-station or sub stations, thermostats and alarm-transmitting devices in a branch at said sub-station or sub-stations, whereby the circuit may be closed and a sig nal transmitted, a circuit-changer for including said branch in the main line, said circuitchanger being automatically operated by the closing or locking of a door, substantially as described.

2. In a combined telephonic and electric automatic fire-alarm system, the combination, \with a main line, of an annunciator, a normal ground-terminal, an alarm-circuit including a relay and main battery, the said relay controlling a local-battery circuit comprising a recorder and bell,and a circuitchanger whereby the main line may be at will transferred from the normal ground-terminal to the alarmcircuit, all at a central station,or at a station electrically connected therewith, and of telephonic instruments, a normal ground therefor, a fire-alarm circuit comprising a suitable number of normally-open branch circuits capable of being attached in derived circuit to the main line, each provided with a series of thermostats and an alarm-transmitting instrument, a local alarm-bell included in the main stem of the said branch circuits, aseparate ground branch including a high resistance bridged by a condenser permanently attached to the said main stem of said branch circuits, a normally open ground circuit branching to each thermostat and adapted to be brought into contact by the action of said thermostats when a predetermined temperature is reached with the derived main-line branch circuits, and a circuit-changer actuated automatically by the closing or locking of a door to set the alarm by attaching the firealarln circuits to the main line, all at one or more sub-stations, substantially as described.

3. In a combined telephonic and electric automatic fire-alarm system, the combination at a sub-station with a common main line, of said system of telephone and call-signal instruments included in said main line, a normallyopen fire-alarm circuit or series of branch circuits ordinarily disconnected from said main line but adapted to be connected in derived circuit therewith, a circuit changer or controller adapted to be actuated automatically upon the closing of the sub-station to eifect such connection, a ground-wire for each of the said branch circuits,adapted to bebrought in connection therewith by the action of thermostats to close the alarm-circuit in case of undue heat, and aseparate ground branch including a high resistance bridged by a con denser and adapted to serve as a ground-terminal for the telephone during the time when the alarm is set and the ordinary telephone ground-terminal thus disconnected, substantially as specified.

4:. In a combined telephonic and automatic electric fire-alarm system and at a sub-station thereof, a main line, telephonic instruments included therein and a normal ground-terminal therefor, combined with a normallyopen fire-alarm circuit fitted with thermostat-s containing branch ground-wires, and adapted to unite said ground-wires with the said normally-open alarm-circuit and thereby to close the same, alocal alarnrbell included in the said alarm-circuit, an earth branch permanently attached to said alarm-circuit, and including a high'resistance bridged by a condenser, and a circuit-changer adapted to be automatically actuated by the closure or locking of a door, and thereby to transfer the main line from its normal ground-connection to the normally-open alarm-circuit and to the high-resistance earth branch, whereby the alarm is set, and the telephone-circuit at the same time maintained continuous, substantially as and for the purposes specified.

5. The combination, with a main electric circuit, a combined telephone and automatic fire-alarm apparatus, and an automatic circuit-changing device, of means, substantially as indicated, for maintaining the telephonic circuit intact while the fire-alarm is set, whereby the telephones may be atall times operated irrespective of the condition of the electrical connections of the main line.

6. The combination, substantially as hereinbefore described, in a combined telephone and automatic fire-alarm system, and at a way substation thereof, of a main circuit, telephone and signaling instruments included therein, a normally-open branch permanently united to said main circuit and terminating in a spring circuit-closer, aseries of fire-alarm circuits, each fitted with thermostats and normally-disconnected ground branches, as described, and connecting by a single line with a contact-plate of said circuit-closer, whereby when the said circuit-closer is actuated the fire-alarm circuits are placed in conp nection with the main line without interrupting the continuity thereof, for the purposes specified.

In testimonywhereof I have signed my name to this specification, in the presence of two subscribing witnesses, this 20th day of June, 1884.

THOS. D. LOCIUVOOD.

\Vitncsscs:

GEO. WILLIs Prnncn, D. E. RICHARDS. 

